The invention generally pertains to gripping mechanisms for rock or earth boring or cutting machines, and more specifically relates to inflatable gripping devices for rock or earth boring or cutting machines.
U.S. Pat. No. 2,946,578 issued to DeSmaele disclosed an excavator apparatus having a fitting circumferentially disposed therearound wherein the fitting comprises a deformable peripheral casing. The casing can be deformed by injection of an appropriate fluid under pressure. The deformed casing comes into tight engagement with the walls of the bore hole to allow a second portion of the machine to move with respect to the first portion of the machine that is gripped within the bore hole by the deformable peripheral casing. As best shown in FIG. 4 of DeSmaele, the deformable peripheral casing is comprised of rim 26, whose diameter exceeds slightly the diameter of body 2 of the excavating machine. The rim 26 covers at its front end a sleeve 138 fastened to the head plate 10. The ceiling between a collar 214 fastened to the rim 26 on the sleeve 138 is effected by a rubber seal 211, clamped to the flange 214 of the rim 26 by reinforced collar 215 bolted to the flange 214. The rim 26 is provided at its middle part with a peripheral reinforced rubber fitting 28 which is applied and held on the rim 26 by a ring 216 comprised of three arcuated parts, assembled by two rings 216a and 216b. The fitting contains three chambers or cushions 200, 201 and 202 arranged circumferentially. These cushions are connected by nipples 217, 218 and 219 to air tubes 203, 204 and 205. It is important to note, as stated above, that ring 216, to which cushion 201 is attached, is comprised of arcuate members that contour the external surface of the excavating machine. Thus, the arcuate segments of ring 216 are specifically designed for an excavating machine having a very precise diameter, and the arcuate members of ring 216 cannot be employed on an excavating machine having a different diameter.
Referring to FIG. 9A of DeSmaele, it is important to note that the length of elastomeric tail fitting 28 and of cushion 201 is substantially greater than the length of ring 216, which forms the base onto which elastomeric tail fitting 28 and cushion 201 are attached. Thus, as cushion 201 is inflated to extend elastomeric tail fitting 28 to brace the excavating machine in the bore hole, elastomeric tail fitting 28 and cushion 201 are subject to extreme movement relative to the tunnel and the excavating machine in a direction parallel with the longitudinal axis of the excavating machine. This relative movement of elastomeric tail fitting 28 and of cushion 201 causes extensive wear at the point of contact between both cushion 201 and elastomeric tail fitting 28 with ring 216, such that cushion 201 and elastomeric tail fitting 28 are prone to tear or separate from ring 216.
In addition to the above patent, which pertains to stabilizing an excavating machine for drilling substantially horizontal bore holes, prior art patents exist for stabilizing a drill string or the like in a substantially vertical bore hole. Exemplary patents include U.S. Pat No. 3,088,532 issued to Kellner; U.S. Pat No. 3,105,561 issued to Kellner; U.S. Pat No. 3,126,971 issued to Kellner; U.S. Pat No. 3,180,436 issued to Kellner et al.; U.S. Pat. No. 3,298,449 issued to Bachman et al.; U.S. Pat. No. 3,376,942 issued to Van Winkle; U.S. Pat No. 4,463,814 issued to Horstmeyer et al.; and U.S. Pat No. 5,186,264 issued to du Chaffaut. As in DeSmaele, all of the above patents disclose elastomeric inflatable portions and substantially arcuate base segments such that the arcuate base segments cannot be applied to a machine having a different diameter. Furthermore, the devices of all of the above patents disclose stabilizing, guiding or bracing members that do not completely circumferentially encase a portion of the exterior surface of the boring or cutting apparatus.
A need thus exists for an inflatable gripper assembly for a rock boring or cutting machine having a base member and elastomeric sheet secured in a fluid-tight manner to the base member that is configurable in a first deflated configuration and a second inflated configuration.
A need thus exists for the above type of inflatable gripper assembly in which the base member is planar, such that the inflatable gripper assembly can be installed on a plurality of rock boring or cutting machines, each having a different diameter.
A need further exists for the above type of inflatable gripper assembly wherein the length of the elastomeric sheet, when inflated, is no greater than the length of the base member, and the width of the elastomeric sheet, when inflated, is no greater than the width of the base member, such that movement of the elastomeric sheet relative to the tunnel and parallel with the longitudinal axis of the rock boring or cutting machine is minimized.
A need additionally exists for the above inflatable gripper assembly wherein when the cutting diameter of a rock boring or cutting machine is increased by increasing the diameter of the cutter head of the rock boring or cutting machine, the number of inflatable gripper assemblies attached to the outer surface of the rock boring or cutting machine can be increased, and a lengthening shim having a predetermined depth can be located between each inflatable gripper assembly on the exterior surface of the rock boring or cutting machine.